American John Pollock is sailing down one of Portugal's largest rivers, the Duoro, on a boat made of cork stoppers thus fulfilling his dream of 30 years. Pollock and his friend Garth Goldstein spent months putting the boat together in Washington, where they live.

Seven cork stoppers were wrapped by a rubber band to make a hexagon and many such hexagons were lashed together with fishing nets to make sturdy stacks. A wooden board placed on top was the deck and to secure a mast and oars.